1) Field of the Invention
The invention relates to a device for making sowing furrows in a lawn, provided with a mobile frame having a number of disc-like cutting members disposed adjacently of each other transversely of the direction of forward movement thereof and drivable round a horizontal shaft.
2) Description of the Prior Art
Such devices are known and typically form part of seeder machines with which grass lawns, and the greens of golf courses in particular, can be improved by first cutting furrows therein at regular distances, spreading grass seed therein and subsequently re-closing the furrows. As a rule these machines are herein suspended from the rear part of an agricultural tractor.
The quality of lawns, and particularly the greens of golf courses, can hereby and in combination with regular mowing hereof be preserved for a long period.
Difficulties can arise the older the grass cover becomes. The ground then becomes increasingly more compacted and more difficult to penetrate. In addition, depending on the quality of the maintenance in the recent past, "felt-forming" is often encountered in greens. A felt-like layer is then found to have formed on the green from parts of the grass dying off. This layer is comparatively tough and therefore difficult to cut.
The nature of the difficulties encountered in these conditions during the making of the seed furrows depends on the type of cutting member with which the machine is equipped.
The cutting members can be classified into two types, one type that is provided with a number of leaves or blades extending radially from the shaft of the cutting member and a type with a disc-shaped cutting body. A cutting member of the first type is in fact a chopping or striking member. With its rotating arms such a member can beat its way relatively easily through more compacted ground and also through tough felt layers. On the other hand, parts of the ground respectively the felt layer are therein broken loose, which parts ate then carried along through the forming seed furrow and are thrown up at the rear as loose material that must later be removed. This material can moreover result in blockage of the seed supply means located at the rear.
Disc-like cutting members operate much more cleanly. Such cutting blades on the other hand penetrate less easily into more solid ground and tough felt layers and often have the tendency therein to rise upward out of their active position and to run over the ground and the tough felt layer. In order to nevertheless hold the discs at depth counter to this tendency, a proportionally large external force directed vertically downward has to be exerted and much additional drive power is required. Attempts have already been made to remedy this problem by arranging recesses lying distributed regularly along the periphery of the round cutting disc. Thus obtained was a sort of circular saw which certainly penetrated more easily through more solid ground and tough felt layers but which still transported loose material through the forming seed furrow to the rear and left it behind on the grass cover for improvement.